Automatic controlling system for maintaining safely the running range in the car and method thereof

ABSTRACT

Disclosed is an automatic control system and method for keeping a car at a safe distance in traffic from an obstacle or other car. The inventive automatic control system comprises: a sensing device  100  for sensing a car or an obstacle in front of the system-installed car in the traveling direction; an electronic control unit (ECU)  200  connected to the sensing device  100  and receiving electric signals transmitted from the sensing device  100  as a result of sensing a car or an obstacle so as to render a control command according to a preset program; an accelerator unit  310  for automatically controlling the deceleration of the system-installed car on the basis of the electric signal from the ECU  200 ; a first guide stop unit  315  which operates independently of the accelerator unit  310  and controls the vertical movement of an accelerator pedal  400 ; a brake unit  330  for automatically controlling the braking of the system-installed car on the basis of the electric signal from the ECU  200 ; and a second guide stop unit  350  which operates independently of the brake unit  330  and controls the operation of a brake pedal  400′.

TECHNICAL FIELD

The present invention relates to an automatic control system and methodfor keeping a car at a safe distance in traffic from an obstacle or anyother car. Particularly, the present invention relates to an automaticcontrol system and method for keeping a car at a safe distance intraffic from an obstacle or any other car in the following manner: ifthe car approaches a predetermined deceleration-required distance inrelation to an obstacle, a command for operating a first guide stopunit, which is spaced from an accelerator pedal, and a second guide stopunit, which is connected to a brake pedal, is rendered by controlsignals programmed in an ECU (Electronic Control Unit) so as tosequentially operate the first guide stop unit and the second guide stopunit according to the command, so that the accelerator pedal is pushedupward in the reverse direction by a pneumatic cylinder, therebyreducing the velocity of the car, and then if the car passes thedeceleration-required distance and approaches a braking-requireddistance in relation to the obstacle, the brake pedal is operated by thepneumatic cylinder, thereby braking the car, whereby various accidents,which may occur when a driver (in particular, a handicapped driver)incorrectly operates the accelerator pedal and/or the brake pedal due toconfusion or un-skilled driving, can be prevented before they happen andthe car can be automatically controlled to be kept at a safe distance intraffic from an obstacle or any other car.

BACKGROUND ART

In general, a brake system for a car, such as a foot brake in anordinary car or a hand/foot brake in a car for a handicapped person,employs a manual braking mechanism, which allows the ordinary car or thecar for a handicapped person to be braked only when the brake isoperated by a foot or by a hand.

In order to obviate accidental danger, which may be caused when a driver(in particular, a handicapped driver) incorrectly operates a brake or anaccelerator due to confusion, unskilled driving or the like, KoreanUtility Model Registration Publication No. 1990-405 (hereinafter, to bereferred to as cited reference 1), which is issued on Jan. 30, 1990 andentitled Apparatus for Preventing Car from Collision, discloses atechnique concerning an automatic braking control system, wherein apiston rod of an air cylinder allows a foot brake and a clutch to beautomatically operated when an object comes close to the car from thefront or rear side of the car, thereby preventing an unexpectedaccident.

However, because the above-mentioned apparatus for preventing a car fromcollision lacks a means for allowing a driver to selectively operate theapparatus as desired, there are inconveniences in that the car isstopped regardless of the driver's intention at an area, such as thedowntown, where many objects exist adjacent the car, and in that the caris stopped whenever one or more objects appear from the front and/orrear side of the car regardless of the velocity of the car, whereby thecar may be stopped unlike the driver's intention while the car istraveling slowly.

In order to remove the inconveniences of the apparatus of the citedreference 1, Korean Patent No. 014239 (hereinafter to be referred to as‘cited reference 2’), which is issued on Apr. 1, 1998, discloses aautomatic brake control apparatus for a car, wherein the brake controlapparatus automatically operates the brake of the car on the basis ofsynthetic consideration of the velocity of the car and a distancebetween the car and an object when such an object exists in front of thecar, thereby preventing an unexpected accident before it happens, andthe brake control apparatus drives the brake pedal using a linear motorand an electromagnet, thereby minimizing the costs for installing thebrake control apparatus.

The apparatus of cited reference 2 comprises: a selection switch (SW)which is switched on/off according to a driver's selection as to whetherthe braking operation is to be executed automatically or manually,thereby converting the driver's selection into an electric signal andoutputting the electric signal; a light emission/reception device, whichoutputs an optical signal for detecting a distance between a carequipped with the apparatus and an object existing in front of the car,senses and converts the optical signal reflected by the object into anelectric signal, and then outputs the electric signal; a car's velocitysensing unit which detects and converts the current velocity of the carinto an electric signal and then outputs the electric signal; a controlunit which determines whether an object exists at a short-distance fromthe car as compared to a reference distance value on the basis of theelectric signal inputted from the light emission/reception device whenthe selection switch is switched on, and which determines whether thecurrent velocity of the car is high or not on the basis of the signalinputted from the car's velocity sensing unit when it is determined thatan object exists at a short-distance from the car as compared to thereference distance value, whereby the control unit outputs an operationsignal for automatically operating the brake depending on the determinedresult; and a brake driver for operating a brake pedal depending on theoperation signal inputted from the control unit.

However, according to cited reference 2, in a case in which anunexpected obstacle suddenly appears in front of a car while the cartravels or travels with abrupt acceleration, if a driver (in particular,handicapped driver) does not discover the obstacle in advance, if thedriver is confused after discovering the obstacle, or if the driver isunskilled in driving, the driver may incorrectly step on an acceleratorpedal instead of stepping on a brake pedal, thereby accelerating the carwithout operating the brake system. If so, a large collision accident ora serious loss of life may occur.

In addition, according to cited reference 2, if the distance between thecar and an obstacle in front of the car, the value of which iscalculated by the control unit, is smaller than the reference distancevalue, the controller reads a car's velocity detection signal anddetermines whether the current velocity of the car exceeds a referencevalue. If it is determined that the current velocity of the car exceedsthe reference value, the braking of the car is caused to beautomatically executed. In such a case, however, if the drivercontinuously steps on the accelerator pedal, the braking command may belost due to the acceleration, whereby the car continuously travels, andthe continuous traveling of the car may affect the control unit to suchan extent that the car travels with emergent departure, thereby causingan accident.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention has been made to solve theabove-mentioned problems occurring in the prior art, and an object ofthe present invention is to provide an automatic control system andmethod for keeping a car at a safe distance in traffic from any othercar or an obstacle in the following manner: if the car comes close to anobstacle within a predetermined deceleration-required distance, acommand for operating a first guide stop unit, which is spaced from anaccelerator pedal, and a second guide stop unit, which is connected to abrake pedal, is rendered by a control signal programmed in an ECU(Electronic Control Unit), so as to sequentially operate the first guidestop unit and the second guide stop unit according to the command, sothat the accelerator pedal is pushed upward in the reverse direction bya pneumatic cylinder, thereby reducing the velocity of the car and thenif the car passes the deceleration-required distance and approaches abraking-required distance in relation to the obstacle, the brake pedalis operated by the pneumatic cylinder, thereby braking the car, wherebyvarious accidents, which may occur when a driver (in particular, ahandicapped driver) incorrectly operates the accelerator pedal and/orthe brake pedal due to confusion or un-skilled driving, can be preventedin advance and the safe distance in traffic can be automatically kept.

Technical Solution

In order to achieve the above-mentioned object, there is provided anautomatic control system for automatically keeping a car at a safedistance in traffic from any other car or an obstacle, comprising: asensing device 100 for sensing a car or an obstacle in front of thesensing device-equipped car in the traveling direction; an ECU(Electronic Control Unit) 200 which is connected with the sensing device100 and receives electric sensing signals which are transmitted from thesensing device 100, so as to render a control command according to apreset program; and a deceleration/braking control unit 300, wherein thedeceleration/braking control unit 300 comprises: an accelerator unit 310for automatically controlling the deceleration of the car on the basisof an electric signal from the ECU 200; a first guide stop unit 315 forcontrolling the upward and downward movement of the accelerate pedal400, the first guide stop unit 300 being operated independently of theaccelerator unit 310; a brake unit 330 for automatically controlling thebraking of the car on the basis of an electric signal from the ECU 200;and a second guide stop unit 350 for controlling the movement of a brakepedal 400′.

According to another aspect of the present invention, there is alsoprovided a control method for keeping a car at a safe distance intraffic from any other car or an obstacle using the inventive automaticcontrol system, comprising steps of: initializing all sensing signals ina sensing device 100 when a main power source of the car is switched onand the accelerating operation is initiated by an accelerator pedal 400(S20); determining whether a deceleration/braking control unit 300 isswitched on, the deceleration/braking control unit being connected withthe sensing device 100 and an ECU 200 (S30); projectinglong-distance/short-distance optical signals to an obstacle in front ofthe car so as to sense the obstacle from an external sensor 110 of thesensing device 100 when the deceleration/braking control unit 300 isswitched on (S40); calculating an actual distance between the car andthe obstacle which is sensed in the sensing step (S40), the calculationbeing performed by the a calculation unit 220 of the ECU 200 (S50);determining whether the actual distance between the car and the obstaclecalculated in the calculation step (S50) is larger than a referencedistance value, which is referred to by a lookup table, with referenceto the lookup table, which is previously stored in a ROM 260 (S60);operating a guide stop plate 40, so that the guide stop plate 40 movesso as to automatically move the accelerator pedal 400 to its originalposition, when the actual distance between the car and the obstaclecalculated in the distance determination step (S60) is smaller than thereference distance value of the lookup table, the operation of the guidestop plate 40 being caused by a first guide stop unit 315 according to asignal transmitted to the first guide stop unit 315 from a travelingsensing device 130 through the ECU 200 (S70); and operating a brake unit330 so as to operate a second guide stop unit 350, thereby operating thebrake pedal 400′ (S80).

ADVANTAGEOUS EFFECTS

As described above, according to the inventive automatic control systemand method for keeping a car at a safe distance in traffic from anobstacle, if the car comes close to the obstacle within a predetermineddeceleration-required distance in relation to an obstacle, a command foroperating a first guide stop unit, which is spaced from an acceleratorpedal, and a second guide stop unit, which is connected to a brakepedal, is rendered by a control signal programmed in an ECU (ElectronicControl Unit), so as to sequentially operate the first guide stop unitand the second guide stop unit according to the command, so that theaccelerator pedal is pushed upward in the reverse direction by apneumatic cylinder, thereby reducing the velocity of the car and then ifthe car passes the deceleration-required distance and approaches abraking-required distance to the obstacle, the brake pedal is operatedby the pneumatic cylinder, thereby braking the car. As a result, variousaccidents, which may occur when a driver (in particular, a handicappeddriver) incorrectly operates the accelerator pedal and/or the brakepedal due to confusion or unskilled driving, can be prevented in advanceand the safe distance in traffic can be automatically maintained. Inother words, when an obstacle is positioned in front of a car within areference distance required for braking, the inventive automatic controlsystem and method for keeping a car at a safe distance in traffic allowsautomatic braking to be performed regardless of whether the driveraccelerates or brakes the car due to confusion or unskilled driving,whereby the inventive system and method are useful in reducing thebraking distance of the car until the driver performs a brakingoperation after discovering an obstacle, thereby enhancing the brakingeffect. In addition, as the accelerator pedal and brake pedal areautomatically controlled depending on a distance between a car and anobstacle in front of the car, the velocity of the car and the weathercondition around the car, while the car travels forward or travels withacceleration, it is possible to keep the car at a distance from theobstacle so as to exclude a danger of collision.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of an automatic control system for keeping acar at a safe distance in traffic from an obstacle according to anembodiment of the present invention;

FIG. 2 is a detailed block diagram of a sensing device and an electroniccontrol unit of the inventive automatic control system for keeping a carat a safe distance in traffic from an obstacle;

FIG. 3 is a cross-sectional view showing a state in which an acceleratorpedal is operated before the first guide stop unit of thedeceleration/braking control unit illustrated in FIG. 1 is operated;

FIG. 4 is a cross-sectional view showing a state in which the firstguide stop unit of the deceleration/braking control unit illustrated inFIG. 1 is moved upward, thereby lifting the accelerator pedal;

FIGS. 5 and 6 are cross-sectional views showing how a brake pedal isoperated before the second guide stop unit of the deceleration/brakingcontrol unit is operated in the inventive automatic control system forkeeping a car at a safe distance in traffic from an obstacle;

FIGS. 7 and 8 are cross-sectional views showing how the second guidestop unit 2 of the deceleration/braking control unit is operated in theinventive automatic control system for keeping a car at a safe distancein traffic from an obstacle;

FIG. 9 is a flowchart of an automatic control method for keeping a carat a safe distance in traffic from an obstacle according an embodimentof the present invention;

FIG. 10 is a flowchart showing how the first stop unit for controllingan accelerator pedal is operated in the inventive automatic controlmethod for keeping a car at a safe distance in traffic from an obstacle;and

FIG. 11 is a flowchart showing how the brake pedal is operated after theaccelerator pedal is operated in the inventive automatic control methodfor keeping a car at a safe distance in traffic from an obstacle.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, several preferred embodiments of the present invention willbe described with reference to the accompanying drawings. The term,automatic control includes a series of procedures for operating guidestop units in connection with automatic braking through a brake pedaland automatic deceleration through an accelerator pedal, which areexecuted according to electric signals transmitted from a preset controlprogram in response to approaching distances of cars which arepositioned before and after, light and left a car provided with theinventive automatic control system (hereinafter, such a car may bereferred to as the system-installed car for the convenience ofdescription), or a change in weather conditions (snow or rain) aroundthe system-installed car while traveling.

Herein, the term reverse direction of accelerator pedal means adirection opposite to the direction for stepping on the acceleratorpedal, and the opposite direction is referred to as forward direction.According to the present invention, a guide stop plate of a first guidestop unit, which is installed below the accelerator pedal, moves upwardso as to forcibly pushes the accelerator pedal upward, i.e., in thereverse direction.

FIG. 1 is a block diagram showing the inventive automatic control systemfor keeping a car at a safe distance in traffic from an obstacle,wherein the inventive automatic control system comprises: a sensingdevice 100 for sensing a surrounding condition; an ECU (electroniccontrol unit) 200 for receiving electric signals from the sensing device100 so as to render a control command, the output terminal of thesensing device 100 being connected to the ECU 200; and adeceleration/braking control unit 300 which is operated by an electricsignal from the ECU 200 so as to control the traveling velocity of acar.

In the inventive automatic control system, the sensing device 100, theECU 200 and the deceleration/braking control unit 300 are switched onwhen a main power source of the car is turned on, and the automaticcontrol system is activated simultaneously when the traveling velocityis increased to about 20 km/hour or more.

The deceleration/braking control unit 300 comprises: an accelerator unit310 for automatically controlling the deceleration of the car on thebasis of an electric signal from the ECU 200; a brake unit 330 forinitiating the braking of the car when an obstacle comes close to thecar within a predetermined distance while the car travels or travelswith abrupt acceleration as the accelerator pedal 400 is operated, thebrake unit 330 being operated independently of the accelerator unit 310;a first guide stop unit 315 operated by an upward or downward movingsignal from the accelerator unit 310; and a second guide stop unit 350operated by an upward or downward moving signal from the brake unit 330.

As shown in detail in FIG. 2, the sensing device 100 senses whether thesystem-installed car comes close to any other car within a predetermineddistance to the front, rear or lateral sides of the other car while thesystem-installed car is traveling, turning left or right, U-turning, orbeing accelerated, and detects a safe distance or an approach distancein relation to an obstacle beyond such a car, and variouscircumferential environments, such as a change in weather conditions,which affect the traveling of the system-installed car.

The ECU 200 comprises a steering wheel rotation signal transmission unit140 and a wiper signal transmission unit 150, which are electricallyinterconnected with each other.

At this time, the steering wheel rotation signal transmission unit 140transmits an angle signal indicative of the rotation (angle) of thesteering wheel of the car to the ECU 200, and the wiper signaltransmission unit 150 transmits a signal indicative of a position of awiper switch of the car to the ECU 200, independently of the steeringwheel rotation signal transmission unit 140.

In addition, the steering wheel rotation signal transmission unit 140transmits a corresponding rotation signal to the accelerator unit 310and the brake unit 330 through the ECU 200 according to the rotatingrange i.e., the range of rotating angle of the steering wheel rotated bythe driver at the time of turning left or right or U-turning whiledriving the car.

More particularly, the steering wheel rotation signal transmission unit140 comprises switches which are switched on or off depending on thepositional states of the steering wheel, i.e., a rightward turningstate, a leftward turning state, and a neutral state. In thisconnection, the switches consist of a rightward turning switch, aleftward turning switch and a neutral switch.

That is, when the car travels along an S-course or changes the travelingdirection, the steering wheel rotation signal transmission unit 140transmits a signal as to whether the deceleration/braking control unit300 is operated or not, depending on the rotating angle of the steeringwheel, to the ECU 200. When the steering wheel is located at an angularposition of 0, which is the original central position of the steeringwheel corresponding to the neutral state, the steering wheel rotationsignal transmission unit 140 does not transmit a steering wheel rotationsignal. When the steering wheel is rotated right, the rightward turningswitch is switched on and the leftward turning switch is switched, andwhen the steering wheel is rotated left, the leftward turning switch isswitched on and the rightward turning switch is switched off.

For example, if the car turns in one direction, the steering wheelrotation signal transmission unit 140 causes the long-distance opticalsensor 112, and the left and right short-distance sensors 114 to beindependently operated, wherein the long-distance optical sensor 112 ispositioned at the center of the bumper of the car, and the left andright short-distance sensors 114 are positioned at the opposite ends ofthe bumper of the car.

If an obstacle is positioned at the left side of the car when the carturns left or U-turns, the left short-distance optical sensor 114 sensesthe obstacle, so that the ECU 200 operates the first guide stop unit315, thereby decelerating the car, and causes the long-distance opticalsensor 112 and the right short-distance optical sensor 114 to beswitched off, thereby preventing unnecessary braking which is caused asthe long-distance optical sensor 112 and the right short-distanceoptical sensor 114 sense an obstacle which is not related to thetraveling direction of the car. However, a program is set in such amanner that if the obstacle is very adjacent to the left side of thecar, the first guide stop unit 315 and the second guide stop unit 350are simultaneously operated so as to provide a braking effect, therebypreventing collision. In addition, when the car turns right, it ispreferable to set the program in such a manner that the long-distanceoptical sensor 112 and the short-distance optical sensors 114 areoperated in contrast to the above-mentioned case in which the car turnsleft.

As shown in FIG. 1, the wiper signal transmission unit 150 iselectrically connected to the ECU 200 and transmits stepwise wipercommand signals to the ECU 200, wherein the stepwise wiper commandsignals are generated depending on the change in weather condition ifthe driver operates the wiper when it rains or snows.

In addition, it is possible for the ECU 200 to connect the wiper signaltransmission unit 150 to the sensing device 100, so that the wipersignal transmission unit 150 transmits electric signals to the ECU usingthe stepwise wiper command signals. In other words, the wiper signaltransmission unit 150 may be connected to the ECU 200 together with thesensing device 100, so that the wiper signal transmission unit 150 willreceive and transmit a wiper operation command to the ECU 200.

The deceleration/braking control unit 300 controls the operation of thefirst guide stop unit via the accelerator unit 310 when the acceleratorunit 300 is operated prior to the brake unit 330 when the distancebetween the car and an obstacle is in a pre-determined range (by meterunit).

In addition, the deceleration/braking control unit 300 executesdeceleration and braking according to a reference value, which is readout from a lookup table, wherein the lookup table is predetermined to besuitable for the change in weather (snow or rain), as the acceleratorunit 310 and the brake unit 330 are operated by electric signalstransmitted according to a program preset in the ECU 200.

Further, the deceleration/braking control unit 300 may comprise a secondguide stop unit 350, to which the brake unit 330 separately connected tothe brake unit 330 regardless of the first guide stop unit 315, which isoperated according to the program preset in the ECU 200, wherein thesecond guide stop unit 350 is operated according to the program which ispreset in the ECU 200.

Therefore, the first guide stop unit 315 and the second guide stop unit350 are independently connected to the ECU 200 and operated according tothe preset program.

Meanwhile, the first guide stop unit 315 is programmed in such a mannerthat information, which allows the second guide stop unit 350 to alwayshave priority in relation to the brake unit 330 of the second guide stopunit 330, is permanently (or semi-permanently) stored in the ECU 200once being recorded in the ECU 200, so that a driver cannot delete orcorrect the information.

Alternatively, the brake unit 330 may be arranged in such a way that thedeceleration and braking are simultaneously switched by the first guidestop unit 315, which is switched on when an acceleration signal isforcibly transmitted as the driver forcibly operates the acceleratorpedal while the short-distance optical sensor 114 operates, as well asthe second guide stop unit 350.

FIG. 2 is a block diagram showing the sensing device and ECU in theinventive automatic control system for keeping a car at a safe distancein traffic from an obstacle.

In the inventive automatic control system, the sensing device 100comprises an external sensing unit 110, which consists oflong-distance/short-distance optical sensors 112 and 114, which areoptical sensors for detecting distance; and a traveling sensing unit 130which is operated simultaneously with the external sensing unit 110 soas to receive a traveling signal of the car and an operation signal ofthe accelerator 400.

In the sensing device 100, the external sensing unit 110 compriseslong-distance/short-distance optical sensors 112 and 114, and a weatherchange sensor, which perform detection in response to a long-distancesignal, a short-distance signal, a traveling signal, and an acceleratorpedal signal, respectively, and the traveling sensing unit 130 comprisesa traveling velocity signal switch 132, which senses the travelingsensor of the car itself, and an accelerator pedal switch for sensing asignal from the accelerator pedal 400 prior to the positional change ofthe accelerator pedal 400, which is rendered by the traveling velocitysignal switch 132.

In addition, the external sensing unit 110 and the traveling sensingunit 130 are electrically connected to the ECU 200 at the output endsthereof, wherein the ECU 200 stores and calculates various signals andsupplies corresponding operation commands to the external sensing unit110 and the traveling sensing unit 130.

Further, the external sensing unit 110 consists of a plurality ofindividual sensing elements, which are installed on the front side,bumper or the like of the car and electrically connected to the ECU 200.

In the external sensing unit 100, the long-distance/short-distanceoptical sensors 114 illuminate long-distance optical sensing signals andshort-distance optical sensing signals and receive signals reflectedfrom an obstacle such as a car, thereby detecting a distance to theobstacle which is positioned in front of them.

The weather change sensor 116 of the external sensing unit 116 receivesweather sensing signals, which are indicative of change in weather,according to various surrounding conditions such as snowing or raining,which may cause the long-distance/short-distance optical sensors 112 and114 to be variable.

When the traveling velocity of the car arrives at about 20 km/hour, thetraveling velocity signal switch 132 causes both the long-distanceoptical sensor 112 and the short-distance optical sensor 114 to beturned on according to a control signal from the ECU 200.

Depending on the traveling velocity of the car, the external sensingunit 110 primarily projects optical signals when an obstacle such as cartraveling in front of the car approaches the car within a predeterminedsafe-distance (within a distance in the range of about 100 m to 50 m) infront of the car, and continuously detects the obstacle.

If the obstacle sensed by the long-distance optical sensor 112approaches the car adjacent to the car within a limit distance, e.g.within about 20 m to the car, the short-distance optical sensor 114,which senses an object positioned within a distance of 20 m to the car,is secondarily operated.

If the obstacle such as a car traveling in front of the car goes awayfrom the car over a deceleration-required distance (e.g., about 50 m),the driver is allowed to freely drive the car.

A signal outputted by the short-distance optical sensor 114 iscalculated by the ECU 200, wherein long-distance signals from thelong-distance optical sensor 112 and short-distance signals from theshort-distance optical sensor 114 are calculated by a program whichrefers to the lookup table which is preset in the ECU 200.

Here, the lookup table is stored in a ROM 260, wherein various referencevalues as to the operating conditions of the accelerator unit 300 arepreviously determined and contained in the lookup table so as to controlthe first guide stop unit 315 and the second guide stop unit 350illustrated in FIG. 1. That is, the lookup table contains referencevalues for a control signal and a traveling velocity signal, which areapplied to the first guide stop unit 315 so as to decelerate the careven if the car is positioned at a normal distance from an obstacle suchas a car in front of the car when the traveling velocity of the car ishigh, and reference values for signals which are indicative of cleanweather, rainy weather, etc., respectively and applied so as to brakethe car according to a weather condition. For example, as compared tothe case of driving a car when it is fine, it is very difficult toobserve an object such as a car traveling in front of the car from thecar if the car travels at a high speed or when it rains. Furthermore,when it rains, the car slips, as a result of which the braking distanceis increased. Therefore, when it rains, reference values for signals fordeceleration and braking of a car are applied even if the car ispositioned at a normal traveling distance from a car or an obstacle infront of the car. As such, the magnitude of a brake control signal for acar, which is in traveling or acceleration, is determined depending on afront obstacle-to-car distance signal, a traveling velocity signal and aweather condition signal, and the calculation unit 220 is driven by thecontrol signal.

Meanwhile, as a result of the calculation of a sensing signal by the ECU200, if the sensing signal is determined as an alarm signal or a warningsignal which is stronger than a noticing signal, the ECU 200 activatesand transmits an operation signal to the accelerator unit 310 whiletransmitting a stop signal to the brake unit 330 of thedeceleration/braking control unit 300, so that the first guide stop unit315 and the second guide stop unit 350 are operated and controlled.

Moreover, when the weather changes and it rains or snows, the ECU 200may cause a control signal, which is supplied from the wiper signaltransmission unit 150 so as to brake the car while the car is travelingin high velocity, to be determined according to a distance sensingsignal for an obstacle positioned in front of the car, a travelingvelocity signal and a weather condition signal.

And, the wiper signal transmission unit 150 transmits a stepwiseoperation command for the driver of the car to operate the wiper of thecar. For example, the wiper signal transmission unit 150 transmits awiper operation command to the ECU 200, so that the first guide stopunit 315 is lifted stepwise in the ratios of 10%, 30% and 50% in thedirection indicated by arrow R₁-R₂ with respect to the accelerator unit310 as shown in FIG. 4 as the wiper is operated in first to thirddivided stages according to the wiper operation command which ispreviously programmed, for example in three steps, and stored in thewiper signal transmission unit 150.

In order to secure the forward field of vision, a driver usuallyoperates a wiper when it rains or snows. At this time, if the driveroperates the switch of the wiper in the second stage, the first guidestop unit 315 is operated.

If the first guide stop unit 315 is operated in this manner, anaccelerator stop plate 40 is operated and lifted in the ratio of 50% inthe reverse direction in relation to the accelerator pedal 400, therebyreducing the ratio to the reference velocity to the traveling velocityto 50% regardless of the operation of the long-distance optical sensor112 and the short-distance optical sensor 114, so that the travelingvelocity of the car is forcibly reduced, wherein the reference velocityis contained in the lookup table of the car.

In particular, because the braking distance of a car is substantiallyincreased under a sub-zero temperature condition in which ice is formedon the road, as compared to the braking distance under a normalcondition, collision due to slippage may occur if the car is abruptlybraked by the operation of the second guide stop unit 350. In order toprevent this, the operation of the second guide unit 350 is programmedin such a manner as to be forcibly stopped by the weather change sensor116, thereby decelerating the car to proper velocity while preventingthe abrupt braking so as to ensure the safe traveling of the car.

Meanwhile, the ECU 200 comprises a calculation unit 220 which receiveselectric signals from the sensing device 100 so as to calculatelong-distance/short-distance optical signals and traveling signals sothat the ECU 200 operates with priority as compared to the acceleratorpedal 400 and the brake pedal 400′, a RAM (Random Access Memory) 240 fortemporarily storing various parameter signals generated while the car istraveling, and a ROM (Read Only Memory) 260 for permanently storinginformation regardless of the maintenance of a power source once theinformation is recorded as a program.

The calculation unit 220 is connected to the output terminal of thesensing device 100 so that the calculation unit receives and performs acontrol command from the sensing device 100, and if a car or an obstaclecomes near to the system-installed car within the reference distance,the long-distance/short-distance optical sensors 112 and 114 as well asthe traveling signal sensor of the traveling sensing unit sense the caror the obstacle and the calculation unit 220 calculates thelong-distance/short distance signals and the traveling signals so thatthe ECU 200 operates with priority as compared to the change of theaccelerator pedal 400 caused by the driver. When the long-distanceoptical sensor 112 detects an object positioned within a predetermineddistance from the system-installed car, the ECU determines that anobstacle is positioned within the predetermined distance on the basis ofthe calculation by the calculation unit 220 and transmits an alarmsignal to the deceleration/braking control unit 300.

In addition, the RAM 240 of the ECU 200 is electrically connected withthe calculation unit 220 and stores various signals produced while thecar is traveling, that is variable signals of the sensing device 100 andthe wiper signal transmission unit 150.

In addition, the ROM 260 of the ECU 200 is electrically connected withthe calculation unit 220 and the RAM, wherein the ROM is a memory devicewhich does not allow deletion or correction of data or informationrecorded therein, whereby even if electric power is not supplied to theROM 260, the data stored in the ROM is not temporarily erased, and theinformation, which is recorded as a program in the ROM, is permanentlystored regardless of maintaining the power source for the ROM 260. Inaddition, the ROM stores data required for voice information as well asfor an LCD (liquid crystal display) device installed within the car inthe form of electronic signals.

In other words, if it is determined that sensing signals calculated bythe calculation unit 220 of the ECU 200 indicate dangerous situation,the ECU transmits an alarm signal to the LCD device while transmitting astop signal to the brake unit 330, so that the driver can recognize thealarm signal. In addition, the alarm signal causes the ROM 260 of theECU 200 to output voice data previously stored in the ROM 260.

FIGS. 3 and 4 are cross-sectional views showing the acting relationshipfor controlling the accelerator pedal in the inventive automatic controlsystem for keeping a car at a safe distance in traffic from any othercar or an obstacle. Here, description will be made in terms of theeventual operation of the first guide stop unit 315.

FIG. 3 shows a state in which the accelerator pedal 400 is operatedbefore the first guide stop unit 315 is operated and moved upward, andFIG. 4 shows a state in which the accelerator pedal 400 is moved as thefirst guide stop unit 315 is operated and moved upward.

The first guide stop unit 315 acting on the accelerator pedal 400 of acar by the ECU 200 has a mechanism for acting if a car approaches thecar within a dangerous distance to the front side, the rear side or alateral side of the car or if the car approaches an obstacle within asafe distance when the car travels forward, turns left or right,U-turns, or travels in high speed.

In FIGS. 3 and 4, the first stop unit 315 acting on the acceleratorpedal 400 of the car is mechanically actuated by a solenoid 369according to electric control signals for the accelerator unit 310,which is supplied from the ECU 200.

Here, when the car travels, the accelerator pedal 400 is capable ofbeing moved upward and downward in the direction indicated by arrows A1and A2 by the first guide stop unit 315 under the control of the ECU200. Meanwhile, it can be appreciated from FIGS. 6 and 7 that when thebraking by the brake pedal 400′ is activated so that the second guidestop 350 is to be movable, the solenoid 360′ connected to the secondguide stop 350 is magnetized thereby controlling the second guide stop350′.

Meanwhile, the solenoid 360 is connected to the accelerator unit 310 ofthe accelerator pedal 400 and operated according to the control commandof the accelerator unit 310, which receives the control command from theECU 200, so as to control the abrupt movement of the guide stop plate40.

In addition, the first guide stop unit 315 comprises: a guide stop plate40 which is spaced from the accelerator pedal 400 and moves upward anddownward according to an electric signal from the solenoid 360 connectedto the accelerator unit 360; a support shaft 36 for supporting the guidestop plate 40 in such a manner as to be movable upward and downwardwithin a predetermined angular range; a link 34 which is hinged to theguide stop plate 40 and reciprocates left and right with reference tothe support shaft 36; a piston rod 32 connected to the link 34; apneumatic cylinder 30 for reciprocating the piston rod 32, the pneumaticcylinder 30 having an air inlet port 28, through which air pressure issupplied from an air compressor 26, and an air discharge port 28′ fordischarging air pressure; and a base 20 for anchoring the support shaft36 and the pneumatic cylinder 30 when the guide stop plate 40 retainsits upward and downward movement according to the air pressure (Kg/cm²)which is supplied from the air compressor 26 or discharged from thepneumatic cylinder 30. Here, if the air flow direction is reversed, theair inlet port 28 and the air discharge port 28′ serve as an airdischarge port and an air inlet port, respectively.

The pressure of the air compressor 26 is adjusted according to the airpressure of the air tank thereof, wherein if the pressure is increasedover a predetermined level, the air compressor 25 is switched off,whereas if the air pressure of the air tank decreases below apredetermined level, the compressor 26 is switched on. The pressure canbe determined by referring to the program of the ECU 200.

In addition, the air compressor 26 supplies pressure for maintaining theaccelerator pedal 400 at the upwardly moved or anchored state.

The guide stop plate 40 is automatically moved upward and downward underthe control command of the ECU 200, which is rendered according to acar-to-obstacle distance signal and a traveling velocity signal.Therefore, when an operation signal of the ECU 200 is applied to theaccelerator unit 300, the first guide stop unit 315 controls the upwardand downward movement of the accelerator pedal 400 which is cooperatedwith the guide stop plate 40, thereby braking the accelerator pedal 400.

At this time, as the accelerator 400 is forcibly moved upward by asignal of the ECU 200, the first guide stop unit 315 stops braking as tothe accelerator pedal 400 while remaining in the upwardly moved state.

Here, an electric signal line is electrically interconnected between ECU200 and the solenoid 360 through the accelerator unit 310 of thedeceleration/braking control unit 300. That is, the signal line connectsthe first guide stop unit 315 with the accelerator unit 310 and aircompressor 26 through the solenoid 360, which is turned on or offaccording to an electrical command supplied from the ECU, apart from thebrake unit 330.

FIGS. 7 and 8 are cross-sectional views showing the practical actingrelationship of the second guide stop 350 of the deceleration/brakingcontrol unit in the inventive automatic control system for keeping a carat a safe distance in traffic from any other car or an obstacle.

As shown in FIGS. 7 and 8, the mechanism applied to the brake pedal 400′is configured in such a manner as to be operated according to aprinciple which is similar to the mechanism of the second guide stop 350which is based on the ECU 200.

FIGS. 5 and 6 show how the inventive pneumatic cylinder 50 operates thepiston rod 52, a first link 54, and a second link 56, which cause thesecond guide stop 350 not to operate at all when the driver compressesthe brake pedal 400′ in the direction indicated by arrow B1.

FIGS. 7 and 8 show how the second guide stop 350 is operated so as tomove the brake pedal 400′ according to a condition given through theexternal sensing unit 110 of the sensing device 100 of the car,regardless of the intention of the driver on how to drive the car.

That is, FIG. 8 shows that as the second guide stop unit 350 isoperated, the piston rod 52 of the pneumatic cylinder 50 is moved in thedirection indicated by arrow B2 and is then moved in the directionopposite to arrow B2, so that the first link 54 and the second link 56are operated, thereby moving the brake pedal 400′ up and down.

The above-mentioned second guide stop unit 350 comprises: an aircompressor 26′, which is operated according to an electric signal fromthe solenoid which is installed at the brake pedal 400′ and connected tothe brake unit 330; a pneumatic cylinder 50 having an air inlet port 29,through which air pressure is supplied from the air compressor 26′, andan air discharge port 29′ for discharging air pressure, the pneumaticcylinder 50 being provided with a piston rod 52 which is reciprocated bythe air pressure; and a first link 54 and a second link 56 which arehinged between the brake pedal 400′ and the piston rod 52 of thepneumatic cylinder 50.

The second guide stop unit 350 configured in this manner is operated inthe same manner as the operation of the first guide stop unit 330, inthat an operation signal is transferred to the second guide stop unit350 from the ECU 200 through the brake unit 330 of thedeceleration/braking control unit 300 and the second guide stop unit 350operates the solenoid 360′.

The solenoid 360′ operated in this manner operates the air compressor26′, which compresses air to a predetermined level of pressure andsupplies the compressed air, and the air pressure supplied by the aircompressor 26′ operated in this manner is supplied to the pneumaticcylinder 50 through the air inlet port 29, thereby operating thepneumatic cylinder 50.

If the solenoid 360′ operates the pneumatic cylinder 50 using the aircompressor 26′ as described above, the piston rod 52 of the pneumaticcylinder 50 is operated, thereby moving the brake pedal 400′ through thefirst link 54 and the second link 56.

If the air flow direction is reversed in connection with the air inletport 29 and the air discharge port 29′, the air discharge port 29′ fordischarging air pressure will serve as an air inlet port 29.

Therefore, the inventive automatic control system for keeping a car at asafe distance in traffic from another car or an obstacle can secure asafe distance in traffic while the car is traveling through a mechanismin which the first guide stop unit 315 moves the guide stop plate 40 inrelation to the accelerator pedal 400 so as to control the velocity ofthe car and a mechanism in which the second guide stop unit 350 forbraking is acted on the brake pedal 400′ so as to control the velocityof the car.

The step for operating the automatic control system according to anembodiment of the present invention (S70), by which the guide stop plate40 of the inventive automatic control system is moved upward so as tomove the accelerator pedal 400 upward, will described later withreference to FIG. 5.

Now, the control method using the inventive automatic control system forkeeping a car at a safe distance in traffic from another car or anobstacle will be described.

FIG. 9 is a flowchart showing the sequence of an automatic controlmethod for decelerating or braking a car according to an embodiment ofthe present invention.

As shown in FIG. 9, according to the control method using the automaticcontrol system for keeping a car at a safe distance from another car oran obstacle, a main power source of the car is initially applied, and ifthe acceleration through the accelerator pedal 400 is initiated, allsensing signals within the sensing device 100 are initialized (S20).

Thereafter, the ECU 200 electrically connected to the sensing device 100determines whether the deceleration/braking control unit 300 is switchedon or not (S30).

If the deceleration/braking control unit 300 is switched on, the ECU 200renders the external sensing unit 110 of the sensing device 100 toproject long-distance/short-distance signals to an obstacle positionedadjacent the car so as to sense the obstacle (S40).

If it snows or rains while performing the step of projectinglong-distance/short-distance signals so as to sense the obstacle (S40)and the driver of the car operates the wiper of the car, whereby thewiper signal transmission unit 150 is operated, the wiper signaltransmission unit 150 checks stepwise command signals according to aprogram which has been previously set for the wiper, and if it isdetermined that there is a change in the stepwise command signals, thewiper signal transmission unit 150 supplies stepwise signals to the ECU200, so that the deceleration/braking control unit 300 could be driven.

In addition, the distance between the car and the obstacle, which issensed in the sensing step S40 is calculated by the calculation unit 220of the ECU 200 (S50). That is, the calculation unit 220 of the ECU 200reads the sensing signals inputted from the sensing device 100 so as tocalculate the distance from the car to the obstacle in front of the car.

Next, the ECU 200 determines whether the calculated distance exceeds areference value or not. That is, it is determined whether the obstaclein front of the car is positioned near or remote from the car ascompared to the reference value (S60).

If the obstacle approaches the car in the reference value determiningstep (S60), the guide stop plate 40 of the first guide stop unit 315 isoperated. For example, if the distance determined by the ECU is in therange of about 50 to 20 m, the guide stop plate is automatically movedupward, whereas if the distance is out of this range, the guide stopplate 40 is returned to its original position.

If the traveling velocity is reduced to not more than 20 Km/hour in thereference value determining step (S60) due to the accumulation of carson the road, the guide stop plate 40 is moved upward according to acommand programmed in the ECU 200 as in the mode of operating theweather change changing device 116, so that the traveling velocity ofthe car is reduced to 50% of the reference velocity, which has beenpreviously set in the lookup table of the car, thereby forcibly reducingthe velocity of the car.

According to the method using the inventive automatic control system, ifthe accelerator pedal 400 is moved upward and downward in a state inwhich the main power source of the car is applied, the ECU renders acontrol command for the accelerator pedal 400 connected to the firstguide stop unit 315 with reference to the lookup table for automaticcontrol of the braking of the car, wherein the lookup table isprogrammed and stored in the ROM 260 of the ECU 200, thereby initiatingthe operation of the inventive automatic control system.

More specifically, if the operation of the automatic control system isinitiated as described above, the ECU 200 initializes all variablesstored in the internal memory and then determines whether thedeceleration/braking control unit 300 is switched on or not (S30).

The deceleration/braking control unit 300 may consist of a switch whichcan be selectively on or off, so that the driver can brake the car asdesired, wherein when the deceleration/braking control unit 300 isswitched off, neither the deceleration nor the braking is automaticallycontrolled. If the deceleration/braking control unit 300 were switchedoff, the ECU 200 continuously detects whether the deceleration/brakingcontrol unit 300 is switched on. However, if the deceleration/brakingcontrol unit 300 is switched on, the sensing device 100 receives sensingsignals from the plural long-distance/short-distance optical sensors 112and 114 for sensing an object in front of the car when an obstacleapproaches the long-distance/short-distance optical sensors 112 and 114and then the sensing device 100 converts the sensing signals intoelectric signals and outputs the electric signals to the ECU 200.

If it is determined that the obstacle in front of the car is away fromthe car at a distance, the value of which is larger than the referencedistance value, in the reference distance value determination step(S60), the accelerator pedal 400 and the brake pedal 400′ are normallyoperated by the driver. However, if it is determined that the obstaclein front of the car is away from the car at a distance, the value ofwhich is smaller than the reference distance value, that is, if thecalculated obstacle-to-car distance is smaller than the referencedistance value in the lookup table, in response to a signal from thetraveling sensing device 130, the ECU 200 causes the first guide stopunit 315 to operate the guide stop plate 40, so that the guide stopplate moves upward, whereby the accelerator pedal 400 is automaticallymoved upward to its initial stop position (S70).

Next, if the accelerator pedal is operated in the step of automaticallymoving the accelerator pedal 400 upward (S70), air pressure is producedfrom the pneumatic cylinder 30 connected to the accelerator pedal 400,and the accelerator pedal 400 is released by the air pressure.

In addition, as the accelerator pedal 400 is automatically moved upwardto its initial stop position and at the same time, the brake unit 330 isoperated, the second guide stop unit 330 is operated, thereby moving thebrake pedal 400′ (S80).

In other words, if the accelerator pedal 400 is automatically movedupward to its initial stop position, the ECU 200 commands the secondguide stop unit 350 to operate the pneumatic cylinder 50. As a result,the pneumatic cylinder 50 is operated and thus the piston rod 52connected to the first link 54 and the second link 56 is moved, wherebythe brake pedal 400′ is operated and the car stops.

Therefore, if a car equipped the inventive automatic system for keepingat a safe distance in traffic from a car or an obstacle approacheswithin a dangerous distance in relation to a car or within a safedistance in relation to an obstacle, which is not a car, while travelingforward, turning right or left, U-turning, or traveling with abruptacceleration, the mechanical mechanism implemented by the operationcommand of the ECU 200 renders the first guide stop unit 330 foracceleration to move upward in relation to the accelerator pedal 400,thereby stopping the declination of the accelerator pedal 400 so as tostop the car.

FIG. 10 is a flowchart showing how the first guide stop unit 315 forcontrolling the accelerator pedal is moved upward according theinventive automatic control method for keeping a car at a safe distancein traffic from other cars or obstacles.

As show in FIG. 10, in the step of automatically moving the acceleratorpedal 400 upward (S70), if the car approaches within a very shortdistance, e.g., about 40 m, in relation to an obstacle, the acceleratorunit 310 receives an operation signal, which is rendered by thelong-distance/short distance sensing of the ECU 200, prior to thebraking signal of the brake unit 330 (S402).

If the accelerator unit 310 receives the operation signal (S402), thesolenoid 360 renders the air inlet port 28 and the air discharge port28′ of the pneumatic cylinder 30 to be closed and opened according to acertain level of air pressure supplied or discharged from the aircompressor 360 by an operation signal supplied to the input terminalthereof and an operation signal supplied to the output terminal thereofthrough the electric signal line of the ECU 200, respectively, so thatthe piston rod 32 within the pneumatic cylinder 30 is operated, therebydriving the pneumatic cylinder 30 (S404).

Thereafter, the piston rod 32 within the pneumatic cylinder 30 and thelink 34 connected to the piston rod 32 are moved (S404), and the guidestop plate connected to the link 34 is moved upward; that is, theaccelerator unit 310 operates the guide stop plate 40 through thesolenoid 360 on the basis of an operation signal calculated by thecalculation unit 220 of the ECU (S408).

Then, the guide stop plate 40 pushes upward the accelerator pedal 400,which is positioned adjacent and faces the guide stop plate 40 andcooperated with the guide stop plate, in the reverse direction inrelation to the direction of pressing the accelerator pedal 400 (S410).

Therefore, according to the inventive automatic control method forkeeping a car at a safe distance in traffic from another car or anobstacle, through the guide stop plate 40, the accelerator pedal 400 isoperated so as to reduce the velocity of the car and the brake pedal 400is operated so as to braking the car.

FIG. 11 is a flowchart showing how the brake pedal is operated after theaccelerator pedal is operated in the inventive automatic control methodfor keeping a car at a safe distance in traffic from another car or anobstacle.

The method of operating the brake pedal is same with the process ofoperating the accelerator pedal of FIG. 9, as illustrated in FIGS. 7 and9.

ECU 200 commands the second guide stop unit 350 to operate the pneumaticcylinder 50 through the solenoid 360′ depending on the conditionsdetermined through the sensing device 100, the steering wheel rotationsignal transmission unit 140, and the wiper signal transmission unit150, regardless of the driver's intention in terms of driving the car(S502).

In addition, as the piston rod 52 of the pneumatic cylinder 50 (see FIG.8), the first link 54 and the second link 56 connected to the piston rod52 are operated (S504), and the up and down movement of the brake pedal400′ is controlled through the links, thereby stopping the car.

If the accelerator pedal 400 is automatically moved upward and thus thecar is stopped, the accelerator pedal 400 and the brake pedal 400′return to their original positions according to the control signals fromthe ECU 200, in which case the guide stop plate 40 for operating theaccelerator pedal 400 and the piston pedal 52 for operating the brakepedal 400′ return to their original positions.

Consequently, the inventive mechanical mechanism, in which the guidestop plate 40, which acts on the accelerator pedal 400, is moved upward,whereby pushing the accelerator pedal 400 upward so as to control thevelocity of the car, operates before the car approaches within a safedistance in relation to another car or an obstacle when the car travelsforward, turns right or left, U-turns, or travels with abruptacceleration, whereby the car can be prevented from colliding withanother car or the obstacle.

As described above, according to the present invention, the decelerationand braking of a car are automatically controlled on the basis ofsynthetic determination of the distance between the car and an obstaclein front of the car and the velocity of the car, whereby an unexpectedaccident can be prevented before it happens.

Although several preferred embodiments of the present invention has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

MODE FOR THE INVENTION

Hereinafter, several preferred embodiments of the present invention willbe described with reference to the accompanying drawings. The term,automatic control includes a series of procedures for operating guidestop units in connection with automatic braking through a brake pedaland automatic deceleration through an accelerator pedal, which areexecuted according to electric signals transmitted from a preset controlprogram in response to approaching distances of cars which arepositioned before and after, right and left of a car provided with theinventive automatic control system (hereinafter, such a car may bereferred to as the system-installed car for the convenience ofdescription), or a change in weather conditions (snow or rain) aroundthe system-installed car while traveling.

Herein, the term reverse direction of accelerator pedal refers to adirection opposite to the direction for stepping on the acceleratorpedal, and the opposite direction is referred to as forward direction.According to the present invention, a guide stop plate of a first guidestop unit, which is installed below the accelerator pedal, moves upwardso as to forcibly push the accelerator pedal upward, i.e., in thereverse direction.

FIG. 1 is a block diagram showing the inventive automatic control systemfor keeping a car at a safe distance in traffic from an obstacle,wherein the inventive automatic control system comprises: a sensingdevice 100 for sensing a condition of circumference; an ECU (electroniccontrol unit) 200 for receiving electric signals from the sensing device100 so as to conduct a control command, the output terminal of thesensing device 100 being connected to the ECU 200; and adeceleration/braking control unit 300 which is operated by an electricsignal of the ECU 200 so as to control the driving velocity of a car.

In the inventive automatic control system, the sensing device 100, theECU 200 and the deceleration/braking control unit 300 are switched onwhen a main power source of the car is turned on, and the automaticcontrol system is activated simultaneously when the driving velocity isincreased to about 20 km/hour or more.

The deceleration/braking control unit 300 comprises: an accelerator unit310 for automatically controlling the deceleration of the car on thebasis of an electric signal of the ECU 200; a brake unit 330 forinitiating the braking the car when an obstacle approaches the carwithin a predetermined distance while the car is driven or acceleratedas the accelerator pedal 400, the brake unit 330 being operatedindependently of the accelerator unit 310; a first guide stop unit 315operated by an upward or downward movement signal from the acceleratorunit 310; and a second guide stop unit 350 operated by an upward ordownward movement signal from the brake unit 330.

As shown in detail in FIG. 2, the sensing device 100 senses whether thesystem-installed car approaches any other car within a predetermineddistance to the front, rear or lateral sides of the other car whiletraveling, turning left, right or even in U-turn, or being accelerated,and detects a safe distance or an approach distance to an obstaclebeyond such a car, and various circumferential environments, such aschange in weather conditions, which affect the travel of thesystem-installed car.

The ECU 200 comprises a steering wheel rotation signal transmission unit140 and a wiper signal transmission unit 150, which are electricallyinterconnected with each other.

At this time, the steering wheel rotation signal transmission unit 140transmits an angle signal indicative of the rotation (angle) of thesteering wheel of the car to the ECU 200, and the wiper signaltransmission unit 150 transmits a signal indicative of a position of thewiper switch of the car to the ECU 200, separately from the steeringwheel rotation signal transmission unit 140.

In addition, the steering wheel rotation signal transmission unit 140transmits a corresponding rotation signal to the accelerator unit 310and the brake unit 330 through the ECU 200 according to the rotatingrange i.e., the range of rotating angle of the steering wheel rotated bythe driver at the time of turning left, right or in U-turn while drivingthe car.

More particularly, the steering wheel rotation signal transmission unit140 comprises switches which are turned to ON or OFF depending on thepositional states of the steering wheel, i.e., a turning right state, aturning left state, and a neutral state. In this connection, theswitches consist of a rightward turning switch, a leftward turningswitch and a neutral switch.

That is, when the car travels along an S-course or changes the travelingdirection, the steering wheel rotation signal transmission unittransmits a signal as to whether the deceleration/braking control unit300 is operated or not, depending on the rotating angle of the steeringwheel, to the ECU 200: when the steering wheel is located at an angularposition of 0, which is the original central position of the steeringwheel corresponding to the neutral state, the steering wheel rotationsignal transmission unit 140 does not transmit a steering wheel rotationsignal, when the steering wheel is rotated right, the right-turningswitch is turned to ON and the left-turning switch is turned to OFF, andwhen the steering wheel is rotated left, the left turning switch isturned to ON and the right turning switch is turned to OFF.

For example, if the turn rotates in one direction, the steering wheelrotation signal transmission unit 140 renders the long-distance opticalsensor 112, and the left and right short-distance sensors 114 to beindependently operated, wherein the long-distance optical sensor 112 ispositioned at the center of the bumper of the car, and the left andright short-distance sensors 114 are positioned at the opposite ends ofthe bumper of the car.

If an obstacle is positioned on the left of the car when the car turnsleft or U-turns, the left short-distance optical sensor 114 senses theobstacle, so that the ECU 200 operates the first guide stop unit 315,thereby decelerating the car, and turns the long-distance optical sensor112 and the right short-distance optical sensor 114 to OFF, therebypreventing unnecessary braking which is caused as the long-distanceoptical sensor 112 and the right short-distance optical sensor 114senses an obstacle which is not related to the travel direction of thecar. However, a program is set in such a manner that if the obstacle isvery adjacent to the left side of the car, the first guide stop unit 315and the second guide stop unit 350 are simultaneously operated so as toprovide a braking effect, thereby preventing collision. In addition,when the car turns right, it is preferable to set the program in such amanner that the long-distance optical sensor 112 and the short-distanceoptical sensors 114 are in contrast to the above-mentioned case in whichthe car turns left.

As shown in FIG. 1, the wiper signal transmission unit 150 iselectrically connected to the ECU 200 and transmits stepwise wipercommand signals to the ECU 200, wherein the stepwise wiper commandsignals are generated depending on the change in weather condition ifthe driver operates the wiper when it rains or snows.

In addition, it is possible for the ECU 200 to connect the wiper signaltransmission unit 150 to the sensing device 100, so that the wipersignal transmission unit 150 transmits electric signals to the ECU usingthe stepwise wiper command signals. In other words, the wiper signaltransmission unit 150 may be connected to the ECU 200 along with thesensing device 100, so that the wiper signal transmission unit 150 willreceive and transmit a wiper operation command to the ECU.

The deceleration/braking control unit 300 controls the operation of thefirst guide stop unit via the accelerator unit 310 when the acceleratorunit is operated prior to the brake unit 330 when the distance betweenthe car and an obstacle is within a pre-determined range (by meterunit).

In addition, the deceleration/braking control unit 300 executesdeceleration and braking according to a reference value referenced by alookup table, which is pre-determined to be suitable to the change inweather (snow or rain), as the accelerator unit 310 and the brake unit330 are operated by electric signals transmitted according to a presetprogram of the ECU 200.

Further, the deceleration/braking control unit 300 may comprise a secondguide stop unit 350, to which the brake unit 330 separately connected tothe brake unit 330 regardless of the first guide stop unit 315, which isoperated according to the program which is preset in the ECU 200,wherein the second guide stop unit 350 is operated according to theprogram which is preset in the ECU 200.

Therefore, the first guide stop unit 315 and the second guide stop unit350 are independently connected to the ECU 200 and operated according tothe preset program.

Meanwhile, the first guide stop unit 315 is programmed in such a mannerthat information, which renders the second guide stop unit 350 to alwayshave priority as compared with the brake unit 330 of the second guidestop unit 330, is (semi) permanently stored in the ECU 200 once beingrecorded in the ECU, so that a driver cannot delete or correct theinformation.

Alternatively, the brake unit 330 may be arranged in such a way that thedeceleration and braking are simultaneously switched by the first guidestop unit 315, which is switched ON when an acceleration signal isforcibly transmitted as the driver forcibly operates the acceleratorpedal while the short-distance optical sensor 114 operates, as well asthe second guide stop unit 350.

FIG. 2 is a block diagram showing the sensing device and ECU in theinventive automatic control system for keeping a car at a safe distancein traffic from an obstacle.

In the inventive automatic control system, the sensing device 100comprises an external sensing unit 110, which consists of along-distance optical sensor 112 and a short-distance optical sensor114, which are optical sensors for detecting distance; an a travelingsensing unit 130 which is operated simultaneously with the externalsensing unit 110 so as to receive a traveling signal of the car and anoperation signal of the accelerator 400.

In the sensing device 100, the external sensing unit 110 comprises along-distance optical sensor 112, a short-distance optical sensor 114,and a weather change sensor, which perform detection in response to along-distance signal, a short-distance signal, a traveling signal, andan accelerator pedal signal, respectively, and the traveling sensingunit 130 comprises a traveling velocity signal switch 132, which sensesthe traveling sensor of the car itself, and an accelerator pedal switchfor sensing a signal from the accelerator pedal 400 prior to thepositional change of the accelerator pedal 400, which is rendered by thetraveling velocity signal switch 132.

In addition, the external sensing unit 110 and the traveling sensingunit 130 are electrically connected to the ECU 200 at the output endsthereof, wherein the ECU 200 stores and calculates various signals andsupplies corresponding operation commands to the external sensing unit110 and the traveling sensing unit 130.

Further, the external sensing unit 110 consists of a plurality ofindividual sensing elements, which are installed on the front side,bumper or the like of the car and electrically connected to the ECU 200.

In the external sensing unit 100, the long-distance optical sensor 112and the short-distance optical sensor 114 illuminate long-distanceoptical sensing signals and short-distance optical sensing signals andreceive signals reflected from an obstacle such as a car, therebydetecting a distance to the obstacle which is positioned in front ofthem.

The weather change sensor 116 of the external sensing unit 116 receivesweather sensing signals, which are indicative of change in weather,according to various surrounding conditions such as snowing or raining,which may cause the long-distance/short-distance optical sensors 112 and114 to be variable.

When the traveling velocity of the car is about 20 km/hour, thetraveling velocity signal switch 132 switches both the long-distanceoptical sensor 112 and the short-distance optical sensor 114 onaccording to a control signal from the ECU 200.

Depending on the traveling velocity of the car, the external sensingunit 110 primarily illuminates optical signals when an obstacle such ascar traveling in front of the car approaches the car within apredetermined safe-distance (within a distance in the range of about 100m to 50 m) in front of the car, and continuously detects the obstacle.

If the obstacle sensed by the long-distance optical sensor 112approaches the car adjacent to the car within a limit distance, e.g.within about 20 m to the car, the short-distance optical sensor 114,which senses an object within 20 m, is secondarily operated.

If the obstacle such as a car traveling in front of the car goes awayfrom the car over a deceleration-required distance (e.g., about 50 m),the driver is allowed to freely drive the car.

A signal outputted by the short-distance optical sensor 114 iscalculated by the ECU 200, wherein long-distance signals from thelong-distance optical sensor 112 and short-distance signals from theshort-distance optical sensor 114 are calculated by a program whichrefers to the lookup table which is preset by the ECU 200.

Here, the lookup table is stored in an ROM 260, wherein variousreference values as to the operating conditions of the accelerator unit300 are previously determined and contained in the lookup table so as tocontrol the first guide stop unit 315 and the second guide stop unit 350illustrated in FIG. 1. That is, the lookup table contains referencevalues for a control signal and a traveling velocity signal, which areapplied to the first guide stop unit 315 so as to decelerate the careven if the car is positioned at a normal distance from an obstacle suchas a car in front of the car when the traveling velocity of the car ishigh, and reference values for signals which are indicative of calmweather, rainy weather, etc., respectively and applied to brake the caraccording to the weather conditions. For example, as compared to thecase of driving a car when the weather is fine, it is very difficult toobserve an object such as a car traveling in front of the car from thecar if the car travels at a high speed or when it rains. Furthermore,when it rains, the car slips, as a result of which the distance requiredfor braking and intensity of braking increase. Therefore, when it rains,reference values for signals for deceleration and braking of a car areapplied even if the car is positioned at a normal traveling distancefrom a car or an obstacle in front of the car. As such, the magnitude ofa brake control signal for a car which is traveling or accelerating isdetermined depending on a front obstacle-to-car distance signal, atraveling velocity signal and a weather condition signal, and thecalculation unit 220 is driven by the control signal.

Meanwhile, as a result of the ECU 200 calculating a sensing signal, ifthe sensing signal is determined to be an alarm signal or a warningsignal which is stronger than a noticing signal, the ECU 200 transmitsand activates an operation signal to the accelerator unit 310 whiletransmitting a stop signal to the brake unit 330 of thedeceleration/braking control unit 300, so that the first guide stop unit315 and the second guide stop unit 350 are operated and controlled.

Moreover, when the weather is changed and it rains or snows, the ECU 200may cause a control signal supplied from the wiper signal transmissionunit 150 so as to brake the car while the car is traveling in highvelocity, to be determined according to a distance sensing signal for anobstacle positioned in front of the car, a traveling velocity signal anda weather condition signal.

And, the wiper signal transmission unit 150 transmits a stepwiseoperation command for the driver of the car to operate the wiper of thecar. For example, the wiper signal transmission unit 150 transmits awiper operation command to the ECU 200, so that the first guide stopunit 315 is lifted stepwise in the ratios of 10%, 30% and 50% in thedirection indicated by arrow R₁-R₂ with respect to the accelerator unit310 as shown in FIG. 4 as the wiper is operated in first to thirddivided stages according to the wiper operation command which werepreviously programmed, for example in three steps, and stored in thewiper signal transmission unit 150.

In order to obtain a forward view, a driver usually operates a wiperwhen it rains or snows. At this time, if the driver operates the switchof the wiper in the second stage, the first guide stop unit 315 isoperated.

If the first guide stop unit 315 is operated in this manner, anaccelerator stop plate 40 is operated and lifted in the ratio of 50% inthe reverse direction in relation to the accelerator pedal 400, therebyreducing the ratio of the reference velocity to the traveling velocityto 50% regardless of the operation of the long-distance optical sensor112 and the short-distance optical sensor 114, so that the travelingvelocity of the car is forcibly decelerated, wherein the referencevelocity is contained in the lookup table of the car.

In particular, because the braking distance of a car is substantiallyincreased under a sub-zero temperature condition in which ice is formedon the road, as compared to under normal conditions, collision due toslippage may occur if the car is abruptly braked by the operation of thesecond guide stop unit 350. In order to prevent this, the operation ofthe second guide unit 350 is programmed in such a manner as to beforcibly stopped by the weather change sensor 116, thereby slowing downthe car to proper velocity while preventing the abrupt braking so as toensure safe traveling of the car.

Meanwhile, the ECU 200 comprises a calculation unit 220 which receiveselectric signals from the sensing device 100 so as to calculatelong-distance/short-distance optical signals and traveling signals sothat the ECU 200 operates with priority as compared to the acceleratorpedal 400 and the brake pedal 400′, a RAM (Random Access Memory) 240 fortemporarily storing various parameter signals generated while the car istraveling, and a ROM (Read Only Memory) 260 for permanently storinginformation regardless of the maintenance of a power source once theinformation is recorded as a program.

The calculation unit 220 is connected to the output terminal of thesensing device 100 so that the calculation unit receives and performs acontrol command from the sensing device 100, and if a car or an obstacleapproaches within the reference distance, thelong-distance/short-distance optical sensors 112 and 114 as well as thetraveling signal sensor of the traveling sensing unit sense the car orthe obstacle and the calculation unit 220 calculates thelong-distance/short distance signals and the traveling signals so thatthe ECU 200 operates with priority as compared to the change of theaccelerator pedal 400 caused by the driver. When the long-distanceoptical sensor 112 detects an object positioned within a predetermineddistance, the ECU determines that an obstacle is positioned within thepredetermined distance on the basis of the calculation by thecalculation unit 220 and transmits an alarm signal to thedeceleration/braking control unit 300.

In addition, the RAM 240 of the ECU 200 is electrically connected withthe calculation unit 220 and stores various signals produced while thecar is traveling, that is variable signals of the sensing device 100 andthe wiper signal transmission unit 150.

In addition, the ROM 260 of the ECU 200 is electrically connected withthe calculation unit 220 and the RAM, wherein the ROM is a memory devicewhich does not allow deletion or modification of data or informationrecorded therein, whereby even if electric power is not supplied to theROM 260, the data stored in the ROM is not temporarily erased, and theinformation, which is recorded as a program in the ROM, is permanentlystored regardless of maintaining the power source for the ROM 260. Inaddition, the ROM stores data required for voice information as well asfor an LCD (liquid crystal display) device installed within the car inthe form of electronic signals.

In other words, if it is determined that sensing signals calculated bythe calculation unit 220 of the ECU indicate dangerous situation, theECU transmits an alarm signal to the LCD device while transmitting astop signal to the brake unit 330, so that the driver can recognize thealarm signal. In addition, the alarm signal renders the ROM 260 of theECU 200 to output voice data previously stored in the ROM 260.

FIGS. 3 and 4 are cross-sectional views showing the acting relationshipfor controlling the accelerator pedal in the inventive automatic controlsystem for keeping a car at a safe distance in traffic from other car oran obstacle. Here, description will be made in terms of the practicaloperation of the first guide stop unit 315.

FIG. 3 shows a state in which the accelerator pedal 400 is operatedbefore the first guide stop unit 315 is operated and moved upward, andFIG. 4 shows a state in which the accelerator pedal 400 is moved as thefirst guide stop unit 315 is operated and moved upward.

The first guide stop unit 315 acted on the accelerator pedal 400 of acar by the ECU 200 has a mechanism of acting if a car approaches the carwithin a dangerous distance to the front side, the rear side or alateral side of the car or if the car approaches an obstacle within asafe distance when the car travels forward, turns left or right,U-turns, or travels at a high speed.

In FIGS. 3 and 4, the first stop unit 315 acting on the acceleratorpedal 400 of the car is mechanically actuated by a solenoid 369according to an electric control signal for the accelerator unit 310,which is supplied from the ECU 200.

Here, when the car travels, the accelerator pedal 400 is capable ofbeing moved up or down in the direction indicated by arrows A1 and A2 bythe first guide stop unit 315 under the control of the ECU 200.Meanwhile, it can be appreciated from FIGS. 6 and 7 that when thebraking by the brake pedal 400′ is activated so that the second guidestop 350 is to be movable, the solenoid 360′ connected to the secondguide stop 350 controls the second guide stop 350′ by being magnetized.

Meanwhile, the solenoid 360 is connected to the accelerator unit 310 ofthe accelerator pedal 400 and is operated according to the controlcommand of the accelerator unit 310, which receives the control commandfrom the ECU 200, so as to control the abrupt movement of the guide stopplate 40.

In addition, the first guide stop unit 315 comprises: a guide stop plate40 which is spaced from the accelerator pedal 400 and moves up and downaccording to an electric signal from the solenoid 360 connected to theaccelerator unit 360; a support shaft 36 for supporting the guide stopplate 40 in such a manner as to be movable up and down within apredetermined angular range; a link 34 which is hinged to the guide stopplate 40 and reciprocates left and right with reference to the supportshaft 36; a piston rod 32 connected to the link 34; a pneumatic cylinder30 for reciprocating the piston rod 32, the pneumatic cylinder 30 havingan air inlet port 28, through which air pressure is supplied from an aircompressor 26, and an air discharge port 28′ for discharging airpressure; and a base 20 for anchoring the support shaft 36 and thepneumatic cylinder 30 when the guide stop plate 40 retains its upwardand downward movement according to the air pressure (Kg/cm²) which issupplied from the air compressor 26 or discharged from the pneumaticcylinder 30. Here, if the air flow direction is reversed, the air inletport 28 and the air discharge port 28′ serve as an air discharge portand an air inlet port, respectively.

The pressure of the air compressor 26 is adjusted according to the airpressure of the air tank thereof, wherein if the pressure is increasedover a predetermined level, the air compressor 25 is switched off,whereas if the air pressure of the air tank decreases below apredetermined level, the compressor 26 is switched on. The pressure canbe determined by referring to the program of the ECU 200.

In addition, the air compressor 26 supplies pressure for maintaining theaccelerator pedal 400 at the upwardly moved or anchored state.

The guide stop plate 40 is automatically moved up and down under thecontrol command of the ECU 200, which is rendered according to acar-to-obstacle signal and a traveling velocity signal. Therefore, whenan operation signal of the ECU 200 is applied to the accelerator unit300, the first guide stop unit 315 controls the upward and downwardmovement of the accelerator pedal 400 which is cooperated with the guidestop plate 40, thereby braking the accelerator pedal 400.

At this time, as the accelerator 400 is forcibly moved upward by asignal from the ECU 200, the first guide stop unit 315 stops braking asto the accelerator pedal 400 while remaining in the upwardly movedstate.

Here, an electric signal line is electrically interconnected between theECU 200 and the solenoid 360 through the accelerator unit 310 of thedeceleration/braking control unit 300. That is, the signal line connectsthe first guide stop unit 315 with the accelerator unit 310 and the aircompressor 26 through the solenoid 360, which is turned on or offaccording to an electrical command supplied from the ECU, apart from thebrake unit 330.

FIGS. 7 and 8 are cross-sectional views showing the practical actingrelationship of the second guide stop 350 of the deceleration/brakingcontrol unit in the inventive automatic control system for keeping a carat a safe distance in traffic from another car or an obstacle.

As shown in FIGS. 7 and 8, the mechanism applied to the brake pedal 400′is configured in such a manner as to be operated according to aprinciple which is similar to the mechanism of the second guide stop 350which is based on the ECU 200.

FIGS. 5 and 6 show how the inventive pneumatic cylinder 50 operates thepiston rod 52, a first link 54, and a second link 56, which cause thesecond guide stop 350 not to operate at all, when the driver compressesthe brake pedal 400′ in the direction indicated by arrow B1.

FIGS. 7 and 8 show how the second guide stop 350 is operated so as tomove the brake pedal 400′ according to a condition given through theexternal sensing unit 110 of the sensing device 100 of the car,regardless of the intention of the driver on how to drive the car.

That is, FIG. 8 shows that as the second guide stop unit 350 isoperated, the piston rod 52 of the pneumatic cylinder 50 is moved in thedirection indicated by arrow B2 and then moved in the direction oppositeto arrow B2, so that the first link 54 and the second link 56 areoperated, thereby moving the brake pedal 400′ up and down.

The above-mentioned second guide stop unit 350 comprises: an aircompressor 26′, which is operated according to an electric signal fromthe solenoid which is installed at the brake pedal 400′ and connected tothe brake unit 330; a pneumatic cylinder 50 having an air inlet port 29,through which air pressure is supplied from the air compressor 26′, andan air discharge port 29′ for discharging air pressure, the pneumaticcylinder 50 being provided with a piston rod 52 which is reciprocated bythe air pressure; a first link 54 and a second link 56 which are hingedbetween the brake pedal 400′ and the piston rod 52 of the pneumaticcylinder 50.

The second guide stop unit 350 configured in this manner is operated ina same manner as the operation of the first guide stop unit 330 in thatan operation signal is transferred to the second guide stop unit 350from the ECU 200 through the brake unit 330 of the deceleration/brakingcontrol unit 300 and the second guide stop unit 350 operates thesolenoid 360′.

The solenoid 360′ operated in this manner operates the air compressor26′, which compresses air to a predetermined level of pressure andsupplies the compressed air, and the air pressure supplied by the aircompressor 26′ operated in this manner is supplied to the pneumaticcylinder 50 through the air inlet port 29, thereby operating thepneumatic cylinder 50.

If the solenoid 360′ operates the pneumatic cylinder 50 using the aircompressor 26′ as described above, the piston rod 52 of the pneumaticcylinder 50 is operated, thereby moving the brake pedal 400′ through thefirst link 54 and the second link 56.

If the air flow direction is reversed in connection with the air inletport 29 and the air discharge port 29′, the air discharge port 29′ fordischarging air pressure will serve as an air inlet port 29.

Therefore, the inventive automatic control system for keeping a car at asafe distance in traffic from another car or an obstacle can secure asafe distance in traffic while the car is traveling through a mechanismin which the first guide stop unit 315 moves the guide stop plate 40 inrelation to the accelerator pedal 400 so as to control the velocity ofthe car and a mechanism in which the second guide stop unit 350 forbraking is acted on the brake pedal 400′ so as to control the velocityof the car.

The step for operating the automatic control system according to anembodiment of the present invention (S70), by which the guide stop plate40 of the inventive automatic control system is moved upward so as tomove the accelerator pedal 400 upward, will described later withreference to FIG. 5.

Now, the control method using the inventive automatic control system forkeeping a car at a safe distance in traffic from another car or anobstacle will be described.

FIG. 9 is a flowchart showing the sequence of an automatic controlmethod for decelerating or braking a car according to an embodiment ofthe present invention.

As shown in FIG. 9, according to the control method using the automaticcontrol system for keeping a car at a safe distance from another car oran obstacle, a main power source of the car is initially applied, and ifthe acceleration through the accelerator pedal 400 is initiated, allsensing signals within the sensing device 100 are initialized (S20).

Thereafter, the ECU 200 electrically connected to the sensing device 100determines whether the deceleration/braking control unit 300 is switchedon or not (S30).

If the deceleration/braking control unit 300 is switched on, the ECU 200renders the external sensing unit 110 of the sensing device 100 toproject long-distance/short-distance signals to an obstacle positionedadjacent the car so as to sense the obstacle (S40).

If it snows or rains while performing the step of projectinglong-distance/short-distance signals so as to sense the obstacle (S40)and the driver of the car operates the wiper of the car, whereby thewiper signal transmission unit 150 is operated, the wiper signaltransmission unit 150 checks stepwise command signals according to aprogram which has been previously set for the wiper, and if it isdetermined that there is a change in the stepwise command signals, thewiper signal transmission unit 150 supplies stepwise signals to the ECU200, so that the deceleration/braking control unit 300 can be driven.

In addition, the distance between the car and the obstacle, which issensed in the sensing step S40 is calculated by the calculation unit 220of the ECU 200 (S50). That is, the calculation unit 220 of the ECU 200reads the sensing signals input from the sensing device 100 so as tocalculate the distance from the car to the obstacle in front of the car.

Next, the ECU 200 determines whether the calculated distance exceeds areference value or not. That is, it is determined whether the obstaclein front of the car is positioned near or remote from the car ascompared to the reference value (S60).

If the obstacle approaches the car within the reference valuedetermining step (S60), the guide stop plate 40 of the first guide stopunit 315 is operated. For example, if the distance determined by the ECUis in the range of about 50 to 20 m, the guide stop plate isautomatically moved upward, whereas if the distance is out of thisrange, the guide stop plate 40 is returned to its original position.

If the traveling velocity is reduced to not more than 20 Km/hour in thereference value determining step (S60) due to the accumulation of carson the road, the guide stop plate 40 is moved upward according to acommand programmed in the ECU 200 as in the mode of operating theweather change changing device 116, so that the traveling velocity ofthe car is reduced to 50% of the reference velocity, which has beenpreviously set in the lookup table of the car, thereby forcibly reducingthe velocity of the car.

According to the method using the inventive automatic control system, ifthe accelerator pedal 400 is moved upward and downward in a state inwhich the main power source of the car is applied, the ECU renders acontrol command for the accelerator pedal 400 connected to the firstguide stop unit 315 with reference to the lookup table for automaticcontrol of the braking of the car, wherein the lookup table isprogrammed and stored in the ROM 260 of the ECU 200, thereby initiatingthe operation of the inventive automatic control system.

More specifically, if the operation of the automatic control system isinitiated as described above, the ECU 200 initializes all variablesstored in the internal memory and then determines whether thedeceleration/braking control unit 300 is switched on or not (S30).

The deceleration/braking control unit 300 may consist of a switch whichcan be selectively on or off, so that the driver can brake the car asdesired, wherein when the deceleration/braking control unit 300 isswitched off, neither the deceleration nor the braking is automaticallycontrolled. If the deceleration/braking control unit 300 were switchedoff, the ECU 200 continuously detects whether the deceleration/brakingcontrol unit 300 is switched on. However, if the deceleration/brakingcontrol unit 300 is switched on, the sensing device 100 receives sensingsignals from the plural long-distance/short-distance optical sensors 112and 114 for sensing an object in front of the car when an obstacleapproaches the long-distance/short-distance optical sensors 112 and 114and then the sensing device 100 converts the sensing signals intoelectric signals and outputs the electric signals to the ECU 200.

If it is determined that the obstacle in front of the car is away fromthe car at a distance, the value of which is larger than the referencedistance value, in the reference distance value determination step(S60), the accelerator pedal 400 and the brake pedal 400′ are normallyoperated by the driver. However, if it is determined that the obstaclein front of the car is away from the car at a distance, the value ofwhich is smaller than the reference distance value, that is, if thecalculated obstacle-to-car distance is smaller than the referencedistance value in the lookup table, in response to a signal from thetraveling sensing device 130, the ECU 200 causes the first guide stopunit 315 to operate the guide stop plate 40, so that the guide stopplate moves upward, whereby the accelerator pedal 400 is automaticallymoved upward to its initial stop position (S70).

Next, if the accelerator pedal is operated in the step of automaticallymoving the accelerator pedal 400 upward (S70), air pressure is producedfrom the pneumatic cylinder 30 connected to the accelerator pedal 400,and the accelerator pedal 400 is released by the air pressure.

In addition, as the accelerator pedal 400 is automatically moved upwardto its initial stop position and at the same time, the brake unit 330 isoperated, the second guide stop unit 330 is operated, thereby moving thebrake pedal 400′ (S80).

In other words, if the accelerator pedal 400 is automatically movedupward to its initial stop position, the ECU 200 commands the secondguide stop unit 350 to operate the pneumatic cylinder 50. As a result,the pneumatic cylinder 50 is operated and thus the piston rod 52connected to the first link 54 and the second link 56 is moved, wherebythe brake pedal 400′ is operated and the car stops.

Therefore, if a car equipped the inventive automatic system for keepinga car at a safe distance in traffic from a car or an obstacle approacheswithin a dangerous distance in relation to a car or within a safedistance in relation to an obstacle, which is not a car, while travelingforward, turning right or left, U-turning, or traveling with abruptacceleration, the mechanical mechanism implemented by the operationcommand of the ECU 200 renders the first guide stop unit 330 foracceleration to move upward in relation to the accelerator pedal 400,thereby stopping the declination of the accelerator pedal 400 so as tostop the car.

FIG. 10 is a flowchart showing how the first guide stop unit 315 forcontrolling the accelerator pedal is moved upward according theinventive automatic control method for keeping a car at a safe distancein traffic from other car.

As shown in FIG. 10, in the step of automatically moving the acceleratorpedal 400 upward (S70), if the car approaches within a very shortdistance, e.g., about 40 m, in relation to an obstacle, the acceleratorunit 310 receives an operation signal, which is rendered by thelong-distance/short distance sensing of the ECU 200, prior to thebraking signal of the brake unit 330 (S402).

If the accelerator unit 310 receives the operation signal (S402), thesolenoid 360 renders the air inlet port 28 and the air discharge port28′ of the pneumatic cylinder 30 to be closed and opened according to acertain level of air pressure supplied or discharged from the aircompressor 360 by an operation signal supplied to the input terminalthereof and an operation signal supplied to the output terminal thereofthrough the electric signal line of the ECU 200, respectively, so thatthe piston rod 32 within the pneumatic cylinder 30 is operated, therebydriving the pneumatic cylinder 30 (S404).

Thereafter, the piston rod 32 within the pneumatic cylinder 30 and thelink 34 connected to the piston rod 32 are moved (S404), and the guidestop plate connected to the link 34 is moved upward; that is, theaccelerator unit 310 operates the guide stop plate 40 through thesolenoid 360 on the basis of an operation signal calculated by thecalculation unit 220 of the ECU (S408).

Then, the guide stop plate 40 pushes upward the accelerator pedal 400,which is positioned adjacent and faces the guide stop plate 40 andcooperated with the guide stop plate, in the reverse direction inrelation to the direction of pressing the accelerator pedal 400 (S410).

Therefore, according to the inventive automatic control method forkeeping a car at a safe distance in traffic from another car or anobstacle, through the guide stop plate 40, the accelerator pedal 400 isoperated so as to reduce the velocity of the car and the brake pedal 400is operated so as to braking the car.

FIG. 11 is a flowchart showing how the brake pedal is operated after thebrake pedal is operated in the inventive automatic control method forkeeping a car at a safe distance in traffic from another car or anobstacle.

The method of operating the brake pedal is same with the process ofoperating the accelerator pedal of FIG. 9, as illustrated in FIGS. 7 and9.

ECU 200 commands the second guide stop unit 350 to operate the pneumaticcylinder 50 through the solenoid 360′ depending on the conditionsdetermined through the sensing device 100, the steering wheel rotationsignal transmission unit 140, and the wiper signal transmission unit150, regardless of the driver's intention in terms of how to drive thecar (S502).

In addition, as the piston rod 52 of the pneumatic cylinder 50 (see FIG.8), the first link 54 and the second link 56 connected to the piston rod52 are operated (S504), and the up and down movement of the brake pedal400′ is controlled through the links, thereby stopping the car.

If the accelerator pedal 400 is automatically moved upward and thus thecar is stopped, the accelerator pedal 400 and the brake pedal 400′return to their original positions according to the control signals fromthe ECU 200, in which case the guide stop plate 40 for operating theaccelerator pedal 400 and the piston pedal 52 for operating the brakepedal 400′ return to their original positions.

Consequently, the inventive mechanical mechanism, in which the guidestop plate 40, which acts on the accelerator pedal 400, is moved upward,whereby pushing the accelerator pedal 400 upward so as to control thevelocity of the car, operates before the car comes within a safedistance in relation to another car or an obstacle when the car travelsforward, turns right or left, U-turns, or travels with abruptacceleration, whereby the car can be prevented from colliding with theanother car or the obstacle.

As described above, according to the present invention, the decelerationand braking of a car are automatically controlled on the basis ofsynthetic determination of the distance between the car and an obstaclein front of the car and the velocity of the car, whereby an unexpectedaccident can be prevented before it happens.

Although several preferred embodiments of the present invention has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

The present invention has an advantage in that if a car comes within apre-determined distance in relation to an obstacle due to a driver (inparticular, a handicapped driver) incorrectly operating an acceleratorpedal and/or a brake pedal due to confusion or unskilled driving, thecar can be automatically decelerated and braked, so that the collisionof the car can be prevented and a safe distance in traffic can besecured.

In addition, the present invention has an advantage in that at themoment a critical situation of collision is detected, which may occursuddenly when a car passes by another car or an obstacle, the firstguide stop unit and the second guide stop unit are operated concurrentlyaccording to an operation command of the ECU 200 so as to forcibly movethe accelerator pedal upward, thereby abruptly braking the car byoperating the brake pedal 400′ while preventing the car from beingaccelerated as the accelerator pedal 400 is operated by a driver, as aresult of which various accidents, which may occur as a driver (inparticular, a handicapped driver) incorrectly operates the acceleratorpedal and the brake pedal due to confusion or unskilled driving, can beprevented before happen.

1. An automatic control system for automatically keeping a car at a safedistance in traffic from any other car or an obstacle, comprising: asensing device 100 for sensing a car or an obstacle in front of thesensing device-equipped car in the traveling direction; an ECU(Electronic Control Unit) 200 which is connected with the sensing device100 and receives electric sensing signals which are transmitted from thesensing device 100, so as to render a control command according to apreset program; and a deceleration/braking control unit 300, wherein thedeceleration/braking control unit 300 comprises: an accelerator unit 310for automatically controlling the deceleration of the car on the basisof an electric signal from the ECU 200; a first guide stop unit 315 forcontrolling the upward and downward movement of the accelerate pedal400, the first guide stop unit 300 being operated independently of theaccelerator unit 310; a brake unit 330 for automatically controlling thebraking of the car on the basis of an electric signal from the ECU 200;and a second guide stop unit 350 for controlling the movement of a brakepedal 400′.
 2. A system as claimed in claim 1, wherein the ECU 200comprises a steering wheel rotation signal transmission unit 140 and awiper signal transmission unit 150, which are electrically connected tothe sensing device
 100. 3. A system as claimed in claim 1, wherein thesensing device comprises: an external sensing unit, which includes along-distance optical sensor 112, a short-distance optical sensor 114,and a weather change sensor 115, which perform sensing in terms of along-distance signal, a short-distance signal, a weather change signal,a travel signal, and an accelerator pedal signal, respectively, whichare inputted in the input terminal of the sensing device 100; and atraveling sensing device 130 which includes a travel velocity signalswitch 132 for sensing the travel velocity of the system-installed caritself, and an accelerator pedal switch 134 which performs sensing priorto the positional variation of the accelerator pedal 400 sensed by thetravel velocity signal switch
 132. 4. A system as claimed in claim 1,wherein the ECU 200 comprises a solenoid 360 connected to theaccelerator unit 310 so as to control the quick movement of theaccelerator pedal
 400. 5. A system as claimed in claim 1, wherein thefirst guide stop unit 315 comprises: a guide stop plate 40 which ispositioned at a distance from the accelerator pedal and moves verticallyaccording to an electric signal from the solenoid 360 connected to theaccelerator unit 310; a support shaft for movably supporting the guidestop plate 40; a link 34 which is hinged to the guide stop plate 40 andreciprocates left and right with reference to the support shaft 36; apiston rod 32 connected to the link 34; a pneumatic cylinder 30, withinwhich the piston rod 32 reciprocates left and right, the pneumaticcylinder 30 having an air inlet port 28, through which air pressure issupplied from an air compressor 26, and an air discharge port 28′ fordischarging air pressure; and a base 20 for anchoring the support shaft36 and the pneumatic cylinder 30 when the guide stop plate 40 maintainsits vertical movement according to the air pressure supplied from theair compressor 26 or discharged from the pneumatic cylinder.
 6. A systemas claimed in claim 5, wherein when an operation signal is rendered fromthe ECU 200 according to a system-installed car-to-obstacle distancesignal and a travel velocity signal, the guide stop plate 40 supplies abraking force in relation to the vertical movement of the acceleratorpedal 400, which is linked with the guide stop plate
 40. 7. A system asclaimed in claim 1, wherein the second guide stop unit 350 comprises: anair compressor 26′ which is installed on the brake pedal 400′ andoperated according to an electric signal of a solenoid 360′ connected tothe brake unit 330; a pneumatic cylinder 50 which has an air inlet port29, through which air pressure is supplied from the air compressor 26′,an air discharge port for discharging the air pressure, and a piston rod52 which is reciprocated by the air pressure; and a first link 54 and asecond link 56 which are hinged between the brake pedal 400′ and thepneumatic cylinder
 50. 8. An automatic control system of keeping a carat a safe distance in traffic from another car or an obstacle: a sensingdevice 100 for sensing a situation in front of the system-installed carin the traveling direction; an ECU 200 connected to the sensing device100 and receiving electric signals transmitted from the sensing device100 as a result of sensing a car or an obstacle so as to render acontrol command according to a preset program; a deceleration/brakingcontrol unit 300 having an accelerator unit 310 for automaticallycontrolling the deceleration of the system-installed car on the basis ofthe electric signal from the ECU 200, a first guide stop unit 315 whichoperates independently of the accelerator unit 310 and controls thevertical movement of an accelerator pedal 400, a brake unit 330 forautomatically controlling the braking of the system-installed car on thebasis of the electric signal from the ECU 200, and a second guide stopunit 350 which operates independently of the brake unit 330 and controlsthe operation of a brake pedal 400′; a steering wheel rotation signaltransmission unit 140 connected to the ECU 200 for supplying a signalindicating an angular rotating range of the steering wheel to thedeceleration/braking control unit 300; and a wiper signal transmissionunit 150 connected to the ECU 200, so as to cause the accelerator unit310 to be moved up and down according to a process of operating a wiper,which is programmed in the ECU
 20. 9. A control method for keeping a carat a safe distance in traffic from any other car or an obstacle,comprising steps of: initializing all sensing signals in a sensingdevice 100 when a main power source of the car is switched on and theaccelerating operation is initiated by an accelerator pedal 400 (S20);determining whether a deceleration/braking control unit 300 is switchedon, the deceleration/braking control unit being connected with thesensing device 100 and an ECU 200 (S30); projectinglong-distance/short-distance optical signals to an obstacle in front ofthe car so as to sense the obstacle from an external sensor 110 of thesensing device 100 when the deceleration/braking control unit 300 isswitched on (S40); calculating an actual distance between the car andthe obstacle which is sensed in the sensing step (S40), the calculationbeing performed by the a calculation unit 220 of the ECU 200 (S50);determining whether the actual distance between the car and the obstaclecalculated in the calculation step (S50) is larger than a referencedistance value, which is referred to by a lookup table, with referenceto the lookup table, which is previously stored in a ROM 260 (S60);operating a guide stop plate 40, so that the guide stop plate 40 movesso as to automatically move the accelerator pedal 400 to its originalposition, when the actual distance between the car and the obstaclecalculated in the distance determination step (S60) is smaller than thereference distance value of the lookup table, the operation of the guidestop plate 40 being caused by a first guide stop unit 315 according to asignal transmitted to the first guide stop unit 315 from a travelingsensing device 130 through the ECU 200 (S70); and operating a brake unit330 so as to operate a second guide stop unit 350, thereby operating thebrake pedal 400′ (S80).
 10. A system as claimed in claim 9, wherein thestep of operating the accelerator pedal (S70) comprises steps of:causing the solenoid 360 to be opened if the car approaches near to theobstacle, so that the accelerator unit 310 receives operation signalsproduced by the long-distance/short-distance sensing by the ECU 200prior to the braking signal of the brake unit 330 (S402); operating apneumatic cylinder 30, wherein if the accelerator unit 310 receives theoperation signals (S402), the pneumatic cylinder 30 is driven by makingthe air inlet port 28 and air discharge port 28′ of the pneumaticcylinder 30 opened and closed, respectively, according to the operationsignals applied to the input and output terminals of the solenoid 360through a signal line (S404); thereafter, moving a piston rod 32 withinthe pneumatic cylinder 30 and a link 34 connected to the piston rod 32(S406); moving upward the guide stop plate 40 connected to the link(S408); and braking the upward and downward movement of the acceleratorpedal 400, wherein the guide stop plate 40 supplies braking force to theaccelerator pedal 400 which is linked with the guide stop plate 40,thereby braking the upward and downward movement of the acceleratorpedal 400 (S410).
 11. A method as claimed in claim 9, wherein the stepof operating the brake pedal 400′ (S80) comprises steps of: operatingthe pneumatic cylinder 50, wherein the operation of the pneumaticcylinder 50 is caused as the ECU 200 renders a command to the secondguide stop unit 350 so as to operate the pneumatic cylinder 50 (S502);and controlling the upward and downward movement of the brake pedal400′, wherein the control of the upward and downward movement of thebrake pedal is performed as the piston rod 52 of the pneumatic cylinder50 is operated, thereby operating a first link 54 and a second link 56,which are hinged between the brake pedal 400′ and the piston rod 52 ofthe pneumatic cylinder 50.